HP Forum Archive 19

[ Return to Index | Top of Index ]

So leaving the board in one piece takes 5 minutes? Message #1 Posted by Egan Ford on 5 Oct 2010, 5:24 p.m.

Re: So leaving the board in one piece takes 5 minutes? Message #2 Posted by Geir Isene on 5 Oct 2010, 5:59 p.m., in response to message #1 by Egan Ford hehe - and making it disappear takes zero minutes.

Re: So leaving the board in one piece takes 5 minutes? Message #3 Posted by Diego Diaz on 5 Oct 2010, 11:34 p.m., in response to message #2 by Geir Isene Hi there, The real problem is that (many) teachers are no longer able to define a problem in such way that "one" only possible answer is correct. Since no mention to the size and/or shape of the pieces (nor the original board) has been done, the problem has as many valid answers as one could imagine. Even the one propossed by the teacher!! and of course the one given by the alumn... and whatever Marie was able to saw... :-) No need for the pieces to be of the same size or shape has been declared in the problem text... so: imagine a square board. Saw it into two identical rectangles. (10 min) Saw one of these rectangles into two squares (5 min) 15 minutes in total, 3 pieces... Saw the other rectangle into two more squares (5 min) 20 minutes in total, 4 pieces... sure you've got the idea... Any amount of pieces can be achieved in any amout of time. In fact, the 10 minutes reference in the problem definition is basically useless since Marie could decide to start sawing a tiny corner... and then another one... or this corner into two pieces... or... whatever. The more obvious is the one proposed by the alumn, three identical pieces from an original rectangle board require two cuts (20 min) Agreed, this teacher should have the license revoked. Cheers from the Caribbean Sea. Diego.

Re: So leaving the board in one piece takes 5 minutes? Message #4 Posted by Walter B on 6 Oct 2010, 1:13 a.m., in response to message #1 by Egan Ford With the picture given the alumn... is definitively "more correct" than the teacher d:-) though I didn't know such a "Kantholz" is called a "board". Consistency is a hard job ... d;-)

Re: So leaving the board in one piece takes 5 minutes? Message #5 Posted by Diego Diaz on 6 Oct 2010, 2:18 a.m., in response to message #4 by Walter B Wow, I didn't even notice that drawing on the right! But certainly this drawing does not show a "board"... may be a "lath". With this new and valuable info another doubt arises: Is Marie the right person to run this exercise? (I mean the sawing one) 10 minutes to saw a thin lath!! oh! C'mon!! ;-))

Re: So leaving the board in one piece takes 5 minutes? Message #6 Posted by Mike Morrow on 6 Oct 2010, 9:39 a.m., in response to message #5 by Diego Diaz Don't gratuitously complicate and obfuscate the discussion. It's a board!!!

How to handle these trick questions Message #7 Posted by Thomas Klemm on 6 Oct 2010, 4:25 a.m., in response to message #1 by Egan Ford

Re: How to handle these trick questions Message #8 Posted by Walter B on 6 Oct 2010, 7:13 a.m., in response to message #7 by Thomas Klemm d:-)) Almost like this:

Re: How to handle these trick questions Message #9 Posted by Norman Dziedzic on 6 Oct 2010, 10:43 a.m., in response to message #8 by Walter B My father was a math teacher for 32 years. One of my favorite stories is from when he was tutoring someone about decimal numbers and my dad asks them, "What does the decimal point do?" After a long pause, the student says, "Well... Mr. Dziedzic... it just sits there." qEd!

Re: How to handle these trick questions Message #10 Posted by Gerson W. Barbosa on 6 Oct 2010, 3:10 p.m., in response to message #8 by Walter B Here is another:

Re: How to handle these trick questions Message #11 Posted by BruceH on 7 Oct 2010, 4:01 p.m., in response to message #10 by Gerson W. Barbosa and another...

[ Return to Index | Top of Index ]

Go back to the main exhibit hall